Deep Sleep Time Measured by Wearable Device Associated with Amyloid Burden in the Elderly with Subjective Cognitive Decline.

Background: Factors other than age and genetics may influence the development of Alzheimer’s disease. In particularly, there is growing evidence that sleep disturbances are associated with increased β-amyloid burden. We investigated the association between sleep characteristics measured with a wearable device and β-amyloid burden in the elderly diagnosed with subjective cognitive decline. Method: We conducted a cross-sectional study in 76 elderly people over 60 years of age with subjective cognitive decline determined by detailed neuropsychological tests. β-amyloid burden was determined by F18-florbetaben positron emission(PET) using two methods. Firstly, visual rating of BAPL (Brain amyloid plaque load) score was used to determine β-amyloid positivity. Secondly, the SUVR (standardized uptake value ratio) values were used for the quantitative evaluation of β-amyloid deposition. Sleep characteristics including total sleep time, number of awakenings during sleep, REM sleep time, deep sleep time, and light sleep time were measured using a wearable device. In addition, we investigated the association between β-amyloid burden and age, ApoE4 genotype, MMSE, and PSQI. Result: Of the 76 subjects included in the analyses, 64.5% were women. The subjects were 70.7 (±6.09) years of age at the beginning of the study. Fifteen subjects were positive and 61 were negative on F18-florbetaben PET. The average SUVR value was 1.27 (±0.220). In particular, we found that deep sleep time was significantly higher in the β-amyloid-negative group (49.5±13.1 minutes) than in the positive group (39.4±13.1 minutes). (p-value 0.009). Conclusion: According to our analysis, a decrease in deep sleep time appears to be associated with amyloid deposition. This is consistent with recent evidence that sleep disturbances may be associated with increased β-amyloid burden. A large-scale prospective study is needed to clarify the causal relationships between deep sleep and amyloid deposition.